Transcript The response of mangrove populations to global climate change in

The Response of Mangrove Populations to
Global Climate Change in a
Human Altered Landscape
Eric Milbrandt, Ph.D.
Marine Laboratory, Sanibel-Captiva
Conservation Foundation
10 October 2007, IAMSLIC
Questions
• What services do mangrove wetlands provide?
• Are populations more or less sensitive to
disturbance in a human-altered landscape?
• How do short term responses differ from long
term responses ?
• Is local adaptation producing traits that have a
higher or lower probability of success?
• What do marine laboratories and coastal
communities have to plan for human-altered
landscapes?
Ecosystem Services
•
•
•
•
Coastal flood protection
Wetland filtration
Nesting habitat for birds
Protection for juvenile
fish from their
predators
• Host for caterpillars,
moths and butterflys
• Carbon sink to buffer
against greenhouse
gases (CO2)
The “Human Element”
• Frequency of powerful, named storms in the tropics
expected to increase
• Southwest Florida protected mangrove shorelines
from development in the early 1970s, however road
construction and mosquito control have degraded
wetland health
–
–
–
–
Tidally restricted areas
Over pruning and illegal trimming
Die-off zones
Pesticide application
Responses to human alteration
• Mangrove populations
were evaluated preand post hurricane
• A large die-off area was
used to mimic sea level
rise, seedling
adaptation was
determined
Fi
R
of
Hurricane Disturbance
• Paired study plots chosen to represent mangroves
altered by human activity and those that were not
• Gradient of wind-induced disturbance to study plots
Path of Hurricane Charley
Friday, August 13, 2004
Green circles are paired
study plots (n = 27) in human
altered and pristine
wetlands on Sanibel Island
Catastrophic Wind
Disturbance
r2=0.83
100
Loss of Canopy (%)
90
80
70
60
50
40
30
20
10
0
2x103 4x103 6x103 8x103 10x103 12x103 14x103 16x103 18x103 20x103
Distance to Eyewall (m)
Size Determines Mortality
1.6
1.4
Log Diameter (cm)
1.2
Non-impacted
Impacted
Severely Impacted
1.0
0.8
0.6
0.4
0.2
0.0
Red
White
Species
Black
Reproduction
Reproducing R. mangle / km
400
2004
2005
300
200
100
**
0
TB '03
CH '03
PI '03
EB '03
MP '05
TB'05
Proffitt, Travis, Milbrandt. 2006. Estuaries and Coasts
Human altered landscapes
Table 2. Post hurricane Rhizophora mangle seedling density in areas
with restricted versus open tidal connections.
Connectivity
Region
ES
CS
NS
CP
Restricted
0.9
0.5
0.0
0.1
Open
4.0
4.3
0.3
0.6
• Complete canopy losses meant that seedlings
were no longer limited by competition for
light
Milbrandt, Boswell, Sokoloff, Bortone, 2006, Impact and response of southwest
Florida mangrove forests to the 2004 Hurricane season. Estuaries and Coasts.
Summary
• Human altered
landscapes respond
differently to
hurricanes
– Fewer seedlings
– Less productive
– Lower recruitment
• Florida Gulf Coast
University M.S.
student continues to
pursue these patterns
Long-term disturbances
• Global climate
change and
associated sea
level rise have led
to dire predictions
about Florida’s
west coast
• How will mangrove
wetlands respond?
What can present conditions
tell us about sea level rise?
• There are many
examples of mangrove
wetlands that have
experienced chronic,
long term exposure to
high water levels
because of human
activity, specifically due
to poor drainage
• Caused by road
construction, mosquito
impoundments
Hydrology
• A road bed (A) restricted tidal flushing (top
panel B) compared to unrestricted shoreline
(bottom panel B)
A
2.5
1.5
1.2
B
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
1.0
0.5
0.0
0
20
40
60
Distance from level (m)
80
Tide Stage NGVD '29 (m)
NGVD '29 (m)
2.0
Tide Stage NGVD '29 (m)
Road
bed
160
170
180
160
170
180
190
200
210
190
200
210
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
Julian Day
Saltwort or mangroves?
• Saltwort has the competitive advantage
0
Batis maritima
A. germinans
in B. maritima
Mortality (%)
20
40
60
80
100
7/7/2005 7/15/2005 7/22/2005 7/29/2005 8/5/2005 8/12/2005 8/19/2005
Research to Support Restoration
• Mangrove
wetlands can be
re-planted to
achieve maximum
benefit to wildlife
“Common Garden”
• Mangroves from Charlotte Harbor and Indian
River Lagoon planted together on both coasts
to observe local adaptation
Local adaptation in mangroves
• Albino trait observed in
offspring; caused by a
mutation in 220 chl a genes
Mutation rates in Tampa Bay
Community Restoration
• Community based restoration in light of human
alterations and in anticipation of global climate
changes can be successful in protecting mangroves
Public Awareness; real time conditions
• SCCF established an in situ coastal observing network,
RECON (http://recon.sccf.org)
SCCF and IAMSLIC
• SCCF Marine Laboratory established in 2002
• Many of the current resource needs (journals
books) provided electronically (FGCU) and
through resource sharing (IAMSLIC)
• Coastal observing systems are on the horizon,
SCCF is providing one of the first streams of
real-time water quality data, how can we
share archived data?
• Is investment in a resource specialist to
handle library and RECON development
worthwhile?
IAMSLIC Lending